NASA announced that its Lunar Atmosphere and Dust Environment Explorer (LADEE) observatory has been encapsulated in the nose cone of the Minotaur V rocket, which is scheduled to carry it into space at 11:27 p.m. ET Friday.

LADEE will blast off from the Wallops Flight Facility on Wallops Island, Va. This mission will be the first to launch a spacecraft beyond Earth's orbit from NASA's Virginia Space Coast launch facility. "We are now ready for launch when the window opens on Sept. 6," the space agency reported on its website.

The Minotaur V rocket, which will carry NASA's lunar probe, waits on its launch pad at the Wallops Flight Facility at Wallops Island, Va. (Image: NASA)

The robotic probe, which is about the size of a small car, will orbit the moon for an expected four-to-five-month mission.

"The moon's tenuous atmosphere may be more common in the solar system than we thought," John Grunsfeld, NASA's associate administrator for science, said last month. "Further understanding of the moon's atmosphere may also help us better understand our diverse solar system and its evolution."

NASA scientists have been working hard to get the probe ready. Engineers put the observatory through final preparations such as checking the spacecraft's alignment, checking its propulsion system for leaks, inspecting and repairing solar panels, and doing final electrical tests. After those requirements were met, engineers put the probe through a rigorous spin testing.

To make sure the spacecraft is perfectly balanced for flight, engineers mounted it onto a spin table and rotated it at approximately one revolution per second. Any imbalance was offset by adding weights to the spacecraft. After that, the same spin test was done once the probe was fully fueled up.

LADEE was then lifted to the top of the rocket, where another spin test was done. With that test successful, the probe was enclosed inside the rocket's nose cone.

About a month after launch, the spacecraft will enter a 40-day test phase. During the first 30 days of that period, LADEE will be testing a high-data-rate laser communication system. If that system works as planned, similar systems are expected to be used to speed up future satellite communications.

After the test period, the probe will begin a 100-day science mission, using three instruments to collect data about the chemical makeup of the lunar atmosphere and variations in its composition. The probe also will capture and analyze any lunar dust particles it finds in the atmosphere.